(Pro 4:23 KJV) Keep thy heart with all diligence; for out of it are the issues of life.
This chapter repeatedly emphasizes the volitional aspect of wisdom. It doesn’t just happen. Yes, it comes from God but there must be buy in on our part. Here we are told to “keep” (watch NASB) (5341), to be alert.
This Hebrew word is translated multiple ways in both the NASB and KJV. We have keep, guard, observe, preserve and tend. We recognize something of value and we make sure that we pay attention.
Why does the Bible repeat this so often? The majority of uses are in the Wisdom literature. I would guess it is frequent because we tend to get lazy and complacent.
So? Stay alert. Apply yourself. Strength flees when it is not exercised. This is just as true in the mind and spirit as it is in the body. Some people walk. Some people jog. Some hit the gym. You cannot send a surrogate.